Advanced characterisation methods for interface shear resistance for airport overlays

Abstract

It is recognised that the adequacy of bond between an asphalt surface layer and the underlying pavement material is fundamental to good pavement performance. This is even more important in airport pavements where shear forces imparted by braking and turning aircraft are high. Various measures of interface shear resistance are available to characterise the bond of asphalt surface layers. Advanced test methods were developed to measure the shear resistance of the interface between asphalt layers. These methods include monotonic testing in direct shear, as well as repeated load testing in inclined shear mode. Both methods have been utilised to compare the interface shear resistance of runways of different field performance, as well as assessing the impact of rain on interface shear resistance achieved during runway asphalt overlay work. Further, the repeated load test has been used to identify a shear susceptible asphalt mixture, with poor field performance, using the monotonic test results to compare cores from two runways.